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multiplying DecimalFormat number (no longer rounded properly)

I'm basically trying to use DecimalFormat to get to two decimal places. I'm taking two integer values then dividing them and casting to a double I've put in sample values below. When I do as below I get a value that is no longer to two decimal places. It seems to be when multiply by the 3 it loses it's rounding.
DecimalFormat df = new DecimalFormat("#.00");
double d = Double.parseDouble(df.format((double)5/6))*3;
System.out.println(d);
Can you let me know why this occurs and how to fix this?

In the statemet:
double d = Double.parseDouble(df.format((double)5/6))*3;
the formatting is not preserved (Double returns a double).
You could do, e.g.:
System.out.println(df.format(d));

Formatting Double to exactly 2 Decimal places IF required

I require a DecimalFormat or a better equivalent of representing a Double value (in Java) which could be:
25 or 25.5
I need for that to be represented as either a whole number (25) or to two decimal places if it has any (25.50). This is because i'm printing it out as money.
I have the following format already:
DecimalFormat decFormat = new DecimalFormat("##,###.##");
This works perfectly if the Double is a whole number; I get the output $25,000. Except if the value is 25,000.5; it prints $25,000.5 when I need it to be printed as $25,000.50. The problem is as stated in the docs:
# a digit, zero shows as absent
So essentially the last zero is dropped off since it is optional.
I cannot do:
DecimalFormat decFormat = new DecimalFormat("##,###.#0");
as that is not allowed.
How can I achieve this?
Note:
These questions are related but do not cover what I need specifically with the DecimalFormat. Most of the answers suggest using a BigDecimal or printf. Is this the best thing to do? I don't have to use DecimalFormat but prefer to since i've started on that path (lots of code everywhere already using it).
Best way to Format a Double value to 2 Decimal places
How do I round a double to two decimal places in Java?
Round a double to 2 decimal places

This is definitely a bit of a hack, but I don't know if the DecimalFormat syntax allows for anything better. This simply checks to see if the number is real, and formats based on the spec you asked for.
double number = 25000.5;
DecimalFormat df;
if(number%1==0)
df = new DecimalFormat("##,###");
else
df = new DecimalFormat("##,###.00");
System.out.println(df.format(number));

When you need to return Decimal Format value this works
import java.text.DecimalFormat;
/**
* #return The weight of this brick in kg.
*/
public double getWeight()
{
DecimalFormat df = new DecimalFormat("#.##");
double number = ( getVolume() * WEIGHT_PER_CM3 ) / 1000;
//System.out.println(df.format(number));
return Double.valueOf ( df.format( number ) );
}

Convert into 2 decimal points [duplicate]

This question already has answers here:
How to round a number to n decimal places in Java
(39 answers)
Closed 8 years ago.
I have a code here that calculate a rate for payment. It works however certain value will result in numerous number of decimal points. I want the result to be converted into only 2 decimal point. How do I do this? below is the attached code:
double rateConv=(((new Double(4.4) * transaction.getAmount())/100)+(transaction.getAmount()+new Double(0.30)));
System.out.println(rateConv);
transaction.setCurrencyPsy(rateConv);
transaction.setUserId(getLoginUserProfile().getUserId());
transaction.setTransType(WalletConstant.TRANS_DEPOSIT);
transaction.setIsApproved(false);
transaction.setCreateDate(new Date());
transaction.setIsCiTrans(false);
transDAO.save(transaction,getLoginUserProfile(),getText("email.admin"));
if(transaction.getDepositType().equals(WalletConstant.DEPOSIT_WIREDTRANSFER)){
addActionMessage(getText("msg.success.tt"));
}else{
addActionMsg(getText("msg.success"));
}
transaction = new WalletTransaction();
} catch (Exception e) {
e.printStackTrace();
addActionErr(getText("Error in system.Please contact system's administrator."));
return ERROR;
}
execute();
return "paymount";
}
Thanks in advance

Use BigDecimal
BigDecimal bd = new BigDecimal(doubleValue);
bd = bd.setScale(2, RoundingMode.HALF_UP);
return bd.doubleValue();
Here RoundingMode.HALF_UP will round towards "nearest neighbor" unless both neighbors are equidistant, in which case round up.

There are many ways of doing what you have asked for
1.
double d = 1.234567;
DecimalFormat df = new DecimalFormat("#.##");
System.out.print(df.format(d));
2.
double d = 1.234567;
System.out.printf("%1$.2f", d);
but I would never ever use double for money values anyways, I recommend you to take a look at BigDecimals
EDIT: look # Zeeshan ´s answer if you want to convert Double to Big Decimal.
but the best is to ONLY use Big Decimal for money values, then you will never have any rounding issues # converting.

Use DecimalFormat
DecimalFormat df = new DecimalFormat("#.##");
System.out.print(df.format(rateConv));

Try like this:
double amount = 123;
DecimalFormat df = new DecimalFormat();
df.setMaximumFractionDigits(2);
System.out.println(df.format(amount));

How to round 0.0 to 0.00 in java?

I have used the following function
float val=0.0;
DecimalFormat toTheFormat = new DecimalFormat("#.##");
float value=Float.valueOf(toTheFormat.format(val));
But its not suitable for all conditions like "0.0" still "0.0". Its not scale up to "0.00".

Use
DecimalFormat toTheFormat = new DecimalFormat("0.00");
to round to 2 significant digits

try
DecimalFormat toTheFormat = new DecimalFormat("#.00");

Your approach is mistaken. Rounding is a numeric operation that takes a number x and returns another number y which approximates x and has the property that the decimal expansion has only so many digits. Example:
0.123 --> 0.12
But 0.0 and 0.00 are the exact same numbers, there is no point in rounding. What you (maybe) want is to format a number in a certain way on output. For this, see the other answers.

If I use DecimalFormat toTheFormat = new DecimalFormat("#.00");
am getting output as .00 not 0.00
so this would be the correct code
DecimalFormat toTheFormat = new DecimalFormat("#0.00");

Java, rounding a double to two decimal places

I'm trying to round a double to the nearest two decimal places however, it is just rounding to the nearest full number.
For example, 19634.0 instead of 19634.95.
This is the current code I use for the rounding
double area = Math.round(Math.PI*Radius()*Radius()*100)/100;
I can't see where i am going wrong.
Many thanks for any help.

Well, Math.round(Math.PI*Radius()*Radius()*100) is long. 100 is int.
So Math.round(Math.PI*Radius()*Radius()*100) / 100 will become long (19634).
Change it to Math.round(Math.PI*Radius()*Radius()*100) / 100.0. 100.0 is double, and the result will also be double (19634.95).

You can use a DecimalFormat object:
DecimalFormat df = new DecimalFormat ();
df.setMaximumFractionDigits (2);
df.setMinimumFractionDigits (2);
System.out.println (df.format (19634.95));

Do you actually want want to round the value to 2 places, which will cause snowballing rounding errors in your code, or simply display the number with 2 decimal places? Check out String.format(). Complex but very powerful.

You might want to take a look at the DecimalFormat class.
double x = 4.654;
DecimalFormat twoDigitFormat = new DecimalFormat("#.00");
System.out.println("x=" + twoDigitFormat.format());
This gives "x=4.65". The difference between # and 0 in the pattern is that the zeros are always displayed and # will not if the last ones are 0.

The following example came from this forum, but seems to be what you are looking for.
double roundTwoDecimals(double d) {
DecimalFormat twoDForm = new DecimalFormat("#.##");
return Double.valueOf(twoDForm.format(d));
}